DESENVOLVIMENTO INICIAL E EFICIêNCIA DE USO DE áGUA E NITROGêNIO POR MUDAS DE Calophyllum brasiliense, Eucalyptus urograndis, Tabebuia impetiginosa E Toona ciliata 1

摘要

The knowledge about the early development of seedlings is critical to the success of reforestation and planting in natural forests. The aim of this study was to evaluate the initial development and efficiency of water and nitrogen use by seedlings of four native and exotic species (Calophyllum brasiliense (native), Eucalyptus urograndis (exotic), Toona ciliata (exotic) and Tabebuia impetiginosa (native)) with age of approximately 120 days after sowing for 120 days after transplantation in green-house conditions. Destructive samples were carried out to assess the dry biomass (Leaf, Stem, Root and Total), leaf area, the root shoot ratio and total nitrogen in seedlings. Based on these variables, it was calculated the physiological parameters of growth and efficiency of water use, which was obtained by the ratio between the total dry biomass accumulation and evapotranspiration of vessels in the period, determined by daily weighing in a balance bench. At the end of 240 days after sowing, Calophyllum brasiliense and Tabebuia impetiginosa produced more total biomass and Toona ciliata showed higher root shoot ratio. There were no differences between the relative growth rate of the species evaluated. Eucalyptus urograndis, Toona ciliata and Calophyllum brasiliense showed the highest values of leaf area ratio, Toona ciliata, Tabebuia impetiginosa and Eucalyptus urograndis showed the highest values of specific leaf area, Eucalyptus urograndis and Calophyllum brasiliense show the highest values for leaf mass ratio and Tabebuia impetiginosa, Toona ciliata and Eucalyptus urograndis showed the highest values of net assimilation rate. Based on quantification of total nitrogen, Tabebuia impetiginosa and Toona ciliata were the most efficient species in the use of nitrogen. Eucalyptus urograndis presented the highest evapotranspiration while Calophyllum brasiliense and Tabebuia impetiginosa were the most efficient species in water use.